Various healing traditions, medical and otherwise, have used sound to help heal the body. For example, one of the most common therapeutic uses of sound is in music therapy. Music has been clinically proven to reduce heart rates, blood pressure, pain, anxiety, and to otherwise improve patients' moods. The lower the frequency, the more harmonics and overtones are produced; the resulting “sound bath” is the hallmark of key therapeutic benefits.
The Berard Auditory Integration Training Method, or AIT, is a form of audio therapy that uses processed music in which the low and high frequencies have been removed at random. The patient typically listens to two, half-hour sessions each day for a period of ten days. Proponents of the Berard Method claim that it can help with various developmental disorders.
Various studies have investigated these and other auditory aspects of autistic spectrum disorders. For example, in “Are the Non-Classical Auditory Pathways Involved in Autism and PDD?,” Neurol Res. September 2005; 27(6):625-9, the authors conclude that some individuals with autism appear to have an abnormal cross-modal interaction between the auditory and the somatosensory systems. As only the non-classical “extralemniscal” ascending auditory pathways receive somatosensory input, the presence of cross-modal interaction in autistic individuals is reported to be a sign that autism is associated with abnormal involvement of the non-classical auditory pathways. This implies that sensory information is processed by different populations of neurons in non-autistic and autistic individuals.
In “Auditory Hypersensitivity in Children and Teenagers with Autistic Spectrum Disorder,” Arg Neuropsiquiatr September 2004; 62 (313): 797-801, the authors conclude that behavioral manifestations to sounds are not associated with the hypersensitivity of auditory pathways in autistic individuals. Instead, autistic individuals appear to have difficulties with upper processing as may be involved in the limbic system.
In “The Long-Term Effects of Auditory Training on Children with Autism,” J. Autism Dev. Discord. June 1997: 27(e): 347-8, the authors found that verbal and performance I.Q. increased significantly after three to twelve months of auditory training. Their findings suggested that some aspects of both auditory training and listening to selected unmodified music has a beneficial effects on children with autism and sound sensitivity.
Based upon these and other investigations, various audio therapies have been proposed for individuals with Autistic Spectrum disorders, including Asperger's Syndrome, and/or other, emotional and physiological disorders.